No special programming tricks were used.

Linux was built in the 90s. Hardware improved more than a 1000x. Linux virtual machine startup times stayed relatively the same.

Turns out we kept adding junk to the linux kernel + bootup operations.

So all I did was cut and remove unnecessary parts until it still worked.

This ended up also getting boot up times to under 1s. The kernel changes are the 10 commits I made, you can verify here: https://github.com/smol-machines/libkrunfw

There's probably more fat to cut to be honest.